IT WASN鈥橳 just the pink-and-grey colour scheme. Or even the loose tiles. The
thing that Martyn Robinson hated most about his bathroom was the mould. Dark
spots speckled the grout and a fuzzy, grey film clung to the shower curtain. No
sooner had he scrubbed it off, back it came. 鈥淚t was Mould City,鈥� says Robinson,
a naturalist at the Australian Museum in Sydney.
Hardly surprising, really. Robinson and his partner Lynne McNairn had chosen
to live in an old, two-storey, brick-and-fibro house in Narraweena, a soggy
suburb to the north of Sydney. The bedrock is so close to the surface that when
it rains, water oozes out of the ground and turns the garden into a bog. Damp
comes with the territory, and in a poorly ventilated bathroom, mould was
inevitable. It was one long battle against the fuzzy fungus until, one day,
Robinson decided to take on domestic help. He started with one, then three, and
eventually a whole army of cleaners. They were small, cost only bed and board,
and didn鈥檛 use nasty chemicals around the house. They were slugs: a motley crew
of striped ones, red ones and big, fat grey ones.
As a naturalist, Robinson is keen to experiment with biological controls of
all sorts. Since he settled in Narraweena, he has offered houseroom to a whole
menagerie of creatures in return for their doing a few chores. His ultimate aim
is to build up a trouble-free staff of animals that can be left alone to get on
with the job. Already, he has turned up previously hidden talents among some of
the local fauna.
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The slugs were his first employees. 鈥淪ome slugs love mould. They thrive on
it,鈥� says Robinson. 鈥淚 noticed a few came into the house and headed for the
bathroom. A friend of mine had seen slugs eating mould in his house so I thought
I鈥檇 test it out.鈥� Worried that the molluscs would never make it across the vast
expanse of carpet that lay between them and the bathroom, he gathered them up
and carried them to their new home. 鈥淟o and behold, it worked. They kept the
mould down. They didn鈥檛 get rid of it completely but we only needed to do a
little work. They are particularly good at cleaning grout, silicone sealer and
other hard-to-reach places,鈥� he says.
Slugs have a strong homing instinct, foraging in the damp night air and
spending the deadly desiccating daylight hours in a cool, moist retreat.
Robinson provided his new staff with comfortable lodgings in the shape of a
little ceramic pot perforated with stars and crescent moons鈥攖he sort more
usually used to waft perfumed oils around the place. 鈥淭hey soon learnt that was
home,鈥� he says. Each night, the slugs crawled out of the moons and stars and
slithered off on their fungal foray. At daybreak, they crept home where they
were safe from bare feet and torrents of hot water. In the breeding season, the
slugs took a break from housework, heading down the drain and out of the vent
pipe to seek a mate in the garden. After a brief romantic interlude, some came
back, unable to resist Robinson鈥檚 increasingly furry shower curtain. Those that
failed to return were replaced with new recruits from the garden.
Since he took on his first few slugs, Robinson has tried out several species,
hoping to find the perfect home help. The leopard slug is a good mould-grazer,
but tends to slip out of the bathroom at night to explore the house. 鈥淵ou might
step on it during its nightly wanderings, so it wasn鈥檛 ideal,鈥� says Robinson.
The little striped slug鈥攏ot so little at 3 to 5 centimetres long鈥攚as
better. It has a healthy appetite for mould and goes about the job as
energetically as a slug can. The red triangle slug, which can grow up to 10
centimetres, was a bit too picky. 鈥淚t will eat mould but it won鈥檛 go on the
ground. It鈥檚 good for shower curtains but won鈥檛 clean the other parts of the
bathroom.鈥� The best slug for the job turned out to be Limax flava, the
much-maligned great grey slug familiar in European gardens and introduced to
Australia. L. flava is a big, beefy slug, 9 centimetres at full
stretch, so it eats a lot of mould. But it鈥檚 also pretty sluggish, for want of a
better word, and doesn鈥檛 wander far at night, so there鈥檚 little risk of finding
one squashed into the carpet the next morning.
At one point, great greys, stripys and a young red triangle shared the
workload and Robinson was more than happy with their efforts. They were
efficient and didn鈥檛 stain the carpets as cleaning with bleach did. Eventually,
though, it was time for a new bathroom: that pink-and-grey just had to go.
Freshly plumbed and neatly tiled in green and white, the new bathroom is airy
and bright. The old plastic shower curtain has gone, replaced by a shiny, glass
cubicle. 鈥淲e do have a silicone strip around the shower tray which is hard to
clean and the slugs do that brilliantly,鈥� says Robinson.
Even so, redundancies loomed. It was time to downsize the staff. The
celestial slug house has gone, and the slimmed-down workforce consists of three
small stripy slugs. 鈥淭hey are small enough to fit in the groove of the sliding
door without getting squashed,鈥� says Robinson. 鈥淥ccasionally they get fed up and
crawl down the plughole, but generally they do a good job.鈥�
Robinson has been well and truly bitten by the slug bug and hopes other
people will give them a try. 鈥淚t鈥檚 an alternative for those who can鈥檛 be
bothered scrubbing or who don鈥檛 like chemicals,鈥� he says. 鈥淭hey don鈥檛 remove all
the mould, but they do keep it down to an acceptable level.鈥� For those who don鈥檛
fancy the sight of fat grey slugs in the bath, he is working on a range of
designer slugs in fetching bathroom colours. L. flava varies naturally
from grey to yellow, and also comes in albino. 鈥淭he yellow form is quite
attractive,鈥� says Robinson. 鈥淎nd the white ones can be tinted by feeding them
vegetable dyes鈥攁lthough you have to keep this up or they revert to white
补驳补颈苍.鈥�
Apart from the odd silvery trail up the bathroom wall and a few droppings
that are easily swilled away during the morning shower, slugs don鈥檛 have any
real drawbacks鈥攗nless you collect vintage wines. 鈥淭hey like the mouldy
labels,鈥� warns Robinson. 鈥淭hey eat them, and then you don鈥檛 know what鈥檚 in the
产辞迟迟濒别.鈥�
With Sydney鈥檚 warm, damp climate鈥攁nd especially on Robinson鈥檚 boggy
patch of land鈥攖here鈥檚 plenty of work for a large household staff. Keeping
down cockroaches, for instance. Roaches come in all sizes, from the thumb-sized
Periplaneta species to the smaller but more persistent Blattella
germanica. 鈥淭hey鈥檙e a problem鈥攆or other people,鈥� says Robinson. His house
is so well protected, he sees about one cockroach a month. The first line of
defence is a colony of leaf-tailed geckos鈥攑rickly-looking lizards with
flat, leaf-shaped tails. These particular geckos don鈥檛 have sticky feet and can
only cling by their claws to rough surfaces. They live outside on the brickwork,
where they are active at night. 鈥淭hey form a sort of moat of geckos that insects
have to get past before they can make it into the house,鈥� says Robinson.
Any that do get in risk an encounter with the 鈥渓ounge lizards鈥�, secretive
skinks that skulk by day behind the lounge (that鈥檚 a sofa to non-Australian
speakers). The skinks emerge in the evening to hunt a whole range of unwelcome
guests, including cockroaches, spiders and silverfish. 鈥淵ou hardly notice they
are there. But they鈥檒l eat anything that鈥檚 moving on the ground,鈥� says
Robinson.
Cockroaches might be unpleasant, but termites are a householder鈥檚 worst
nightmare. Given half a chance, they鈥檒l eat the house鈥攗nless something
eats them first. In Narraweena, termites have a natural enemy in the little
black ant. If the ants come across a band of termite workers, they鈥檒l follow
them down into their galleries where they鈥檒l eat termites at every stage of
development from egg to adult. Above ground, any termite king or queen setting
out to found a new nest is fair game. If they land anywhere near the ants
they鈥檙e done for鈥攁nd that鈥檚 one fewer nest to worry about. Robinson and
McNairn are happy to share their home with a few black ants in exchange for a
termite-free house, although the ants themselves can become a nuisance. 鈥淭hey鈥檒l
eat our food too鈥攆rom the sugar to breakfast cereals鈥攁nd they get
everywhere. You might find them living in the teapot, for instance. But we
tolerate them. They patrol the places a human cleaner can鈥檛 get to,鈥� says
Robinson.
Scuttling insects and stationary eggs are relatively easy to deal with, but
in Australia it鈥檚 hard to avoid flying insects, especially mosquitoes. Most
people keep them out with wire screens. Robinson鈥檚 insect screens are woven from
silk and tailor-made by orb spiders. Webs on either side of the ramp leading to
the first-floor entrance create an insect-screened corridor to the house. Golden
orb spiders are best for this job. They build fairly permanent webs, and
although they don鈥檛 always build them in the right place or at the right angle,
the webs can be moved into position by carefully detaching the supporting
strands and fastening them to a more suitable twig or stem. Garden orb spiders
do their bit too, but they have a serious drawback鈥攖hey build a new web
each night, eating the old one the following morning. 鈥淭his means we sometimes
walk straight into a web at night that wasn鈥檛 there during the day,鈥� says
Robinson.
There are plenty of pests left to keep a whole range of wildlife fed, from
dragonflies to bats, to fish and frogs which live in the garden鈥檚 pools and
ponds, even insect-eating sundews and pitcher plants, which thrive on the boggy
ground. And about this time of year, the anti-mosquito task force is swelled by
the arrival of several species of Toxorhynchites鈥攗nusually large
mosquitoes with glittering iridescent bodies and wings. There are dozens of
species of Toxorhynchites around the world and they share one endearing
habit: as larvae they have a voracious appetite for the young of other
mosquitoes. The adult insects suck plant sap and nectar, not blood, and they lay
their eggs in small pools, containers filled with rainwater, tree holes and even
waterlogged footprints in the lawn. The offspring of other mosquitoes don鈥檛 have
much of a chance. A single Toxorhynchites larva can eat its way through
400 smaller mosquito larvae before it reaches adulthood. 鈥淎lthough we鈥檝e still
got plenty of mosquitoes, there are fewer than there might have been,鈥� says
Robinson.
Apart from their battery of biological controls, Robinson and McNairn
restrict their fight against pests to mechanical methods鈥攕quashing snails,
for instance鈥攐r at most, sloshing ecologically friendly soapy water over
bad infestations of scale insects. The result is a garden filled with native
species, from mud-burrowing spiny crayfish to seven species of insect-eating
lizard. Native honeybees, rescued from a fallen tree, nest in two hives that
Robinson has provided, each potentially giving him a litre of lemony-tasting
honey a year. Native wasps have moved into other artificial nest sites鈥攁nd
keep down harmful caterpillars. 鈥淲e provide what the animals want, and they
come,鈥� says Robinson. 鈥淎nd the more diversity there is, the less likely we are
to have pests. Pests may get used to chemicals, but they never get used to being
别补迟别苍.鈥�
And there鈥檚 a bonus. There鈥檚 always a ready supply of new additions to the
household staff. 鈥淲e鈥檒l probably never have a scrupulously clean and tidy house
but we have one that鈥檚 comfortable, entertaining and doesn鈥檛 give us too much
飞辞谤办.鈥�
For anyone thinking of following Robinson鈥檚 example, it鈥檚 probably best to
check that it鈥檚 OK with any other humans living in the house. Fortunately,
McNairn shares Robinson鈥檚 enthusiasm. 鈥淚 like having the critters around,鈥� she
says. 鈥淭hey make our life interesting, and generally you don鈥檛 even know they
are there. They just quietly get on with their jobs and every now and then you
see one of the geckos or slugs and think, that鈥檚 nice, they鈥檙e still here.鈥�
Unless they are spiders, that is. 鈥淭here was a bit of a problem when a large
banded huntsman spider I鈥檇 introduced to the garden took up residence in a
drawer,鈥� admits Robinson. 鈥淲hen Lynne went to take out her favourite grey
jumper, part of it moved under her hand,鈥� he recalls. Her piercing scream
persuaded him to put the spider at the farthest part of the garden. 鈥淚t never
returned,鈥� he says, 鈥減robably because its sound receptors are still ringing.鈥�